This invention relates to processes in which matter is subjected to fluid flow.
In our specification EP-B-68853 there is disclosed apparatus comprising a chamber having an annular fluid inlet disposed beneath an annular region in the chamber and means for directing fluid flow through the inlet into the annular region with vertical and circumferential flow components for moving a bed of matter in the chamber in a band along an annular path in the annular region as the fluid passes through the bed.
This apparatus may be used for treating the fluid and/or the matter as the fluid passes through the bed of matter. During the treatment of matter and/or fluid in this way, the matter is continuously in the flow of fluid as it moves along the annular path. In certain processes such continuous subjection of the matter to the fluid flow can be disadvantageous.
Accordingly, the present invention provides a process in which matter is subjected to fluid flow, comprising providing a flow of fluid in a first annular region having vertical and circumferential flow components, providing a second annular region contiguous with and disposed outwardly of the first region, moving matter in a band continuously around the regions while circulating matter in the band between the regions such that the matter moves into and out of the flow during movement around the regions.
In a preferred embodiment of the invention to be described hereinafter the matter is moved out of the first annular region by centrifugal force and is returned from the second annular region to the first annular region by a slope in a wall means bounding the second annular region.
The process of the invention is particularly, but not exclusively, applicable where there is a heat transfer between the matter and the fluid flow.
The invention also includes apparatus for subjecting matter to fluid flow, comprising a chamber having an annular fluid inlet means disposed beneath a first annular region in the chamber, the chamber having a second annular region contiguous with and disposed outwardly of the first region between the first region and a circumferential wall means of the chamber, means for directing fluid flow through the inlet into the first annular region with vertical and circumferential flow components, and means for moving matter which has moved out of the flow in the first region into the second region by centrifugal force back into the first region.
The invention also includes apparatus for subjecting matter to fluid flow comprising a chamber having a circumferential wall means extending upwardly and disposed radially outwardly, of an annular fluid inlet means, at least a portion of the wall means having a slope towards the annular fluid inlet means whereby the chamber has a first annular region above the annular fluid inlet means and a second annular region between the first region and the wall means, means for directing fluid through the inlet means into the first annular region with vertical and circumferential flow components such that, in use, matter in the chamber is moved in a band continuously along an annular path in the regions, the matter being moved vertically and circumferentially whilst in the first region by the flow therein, being moved out of the flow in the first region into the second region by centrifugal force and being directed back into the first region by the slope of the wall means.
The slope may extend downwardly to the outer edge of the annular fluid inlet means.
The circumferential wall means may comprise a cylindrical portion extending upwardly from a portion having the slope.
The chamber may include second circumferential wall means extending upwardly, and disposed radially inwardly, of the annular fluid inlet means.
This second circumferential wall means may comprise at least a portion having a slope toward the annular fluid inlet means, which slope may extend to the radially inner edge of the annular fluid inlet means.
The means for directing fluid through the inlet into the first annular region with vertical and circumferential flow components may comprise an annular array of at least generally radially extending elongate passage means, each of which has at least one side surface which is inclined such that flow upwardly through the passage means exits with a circumferential flow component.
These passage means may be provided in an annular wall portion, and for example each passage means may comprise a slot extending through the wall portion, both of the at least generally radially extending side surfaces of the slot being inclined circumferentially.
The annular array of passage means may be disposed beneath the annular fluid inlet means and the flow directing means may further comprise respective flow guiding means extending upwardly between the array and locations at or adjacent radially inner and outer edges of the annular inlet means for causing flow through the array to be confined substantially to the first region in the chamber.
One or each of the flow guiding means may comprise aperture means for directing fluid flow into the flow through the array. Preferably the one or each flow guiding means comprises a circumferential wall portion provided with the aperture means. These aperture means may comprise circumferentially spaced apart elongate apertures, each having at least one side surface which is inclined such that flow therethrough exits with a circumferential flow component. Preferably these elongate apertures extend upwardly.
In order that the invention may be better understood, an embodiment thereof, which is given by way of example only, will now be described with reference to the accompanying drawings.